Hermetically sealed switch



Jan. 15, 1957 R. H. JORDAN ETAL 2,777,910

HERMETICALLY SEALED SWITCH Filed June 29, 1953 RN on md bu IN VEN TORS RICHARD "JORDAN BY THEODORE Y. KORSGREN $440411? HERMETICALLY SEALED SWITCH Richard H. Jordan, Mansfield, and Theodore Y. Korsgren, Columbus, Qhio, assignors to Acro iilanuiacturing Company, Columbus, Ohio Application June 29, 1953, erial No. 364,593

6 Claims. (6]. filth-67) This invention relates generally to electrical equipment and in its more particular aspects it is directed to switches, especially of the enclosed or sealed type.

An object of the invention is to provide a switch of compact design which may be suitable for use under water or other liquids or in atmospheres containing explosive gases or other compositions.

A further object of this invention is to provide a hermetically sealed, snap-action switch requiring only slight movement to eflect its operation.

A still further object of the invention is to provide a switch mechanism having a sealed casing containing a snap switch, the casing having an opening covered by a flexible diaphragm through which motion is transferred from an actuating device to the snap switch.

Another object is to provide a switch mechanism of the type mentioned in the preceding paragraph in which 2,777,910 Patented Jan. 15, 195:7

"ice.

Casing 26 has a top wall 30 extending substantially parallel with the bottom wall 28, the top wall being integrally formed with the side wall. The casing 26 encloses the operating parts of the switch mechanism, which parts include a snap switch 31 and a motion transmitting spring arm 32. Snap switch 31 includes three supporting posts 33, 34 and 35, the former carrying a movable contact element 36 and the two latter posts carrying stationary contact elements 37 and 38. All of the posts extend through flanged openings in the bottom wall 28 and are rigidly held in place by dielectric material fused tothe posts and the bottom wall 28. The posts 33, 34 and 35 con-.

nect at their lower ends with terminal members 40, 41 and 42 which extend through slots in the base and are equipped at their ends with threaded sleeves embedded in the base and receiving clamp screws 43 Stationary contact elements 37 and 38 are provided on their contacting surfaces with wear resisting material and are disposed for engagement by button means carried by movable element 56. This element comprises a flexible If strip supported at one end by post 33 and extending into novel manner of securing a flexible diaphragm to a switch casing to prevent the entrance of air or other fluids yet permit linear movement to be transmitted from the outside of the casing to mechanism disposed therein.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred form of embodiment of the invention is clearly shown.

In the drawings:

Fig. 1 is a vertical longitudinal sectional view taken through a switch mechanism formed in accordance with the present invention, the plane of this section being indicated by the line l--I of Fig. 2.

Fig. 2 is a detail horizontal sectional view taken through the switch mechanism on the plane indicated by the line IIII of Fig. 1

Fig. 3 is a detail vertical transverse sectional view taken on theplane indicated by the line Ill-III of Fig. l; and

Fig. 4 is a similar View taken on the plane indicated by the line IVIV of Fig. l.

Referring more particularly to the drawings, the numeral 20 designates a complete switch formed in accordance with the present invention. This switch 20 has a dielectric base 21 which may be molded, pressed or cast, depending upon the material from which it is formed and the desires of the manufacturer. The base may be reinforced on the top and bottom by suitable ribs 22 and 23, the rib on top extending around the periphery of the base and being relieved, as at 24, to provide a shoulder for engaging and locating the lower edge of the side wall 25 of a sheet metal casing 26. Side wall 25 has an internal shoulder 27 formed intermediate of its height for engaging tight relationship.

the space'between contacts 37 and 38. Post 33 also carries a center blade or actuator 44 which is engaged at one end by a U-shaped rolling spring 45, the spring also engaging the movable contact element. In the present form of the invention, element 36 has a central opening and center blade 44 is held in registration therewith. Spring 45 is flexed and has its ends engaged with the center blade and contact element 36, the spring extending through the opening in the contact element. The tendency of the 3 spring to straighten outexertsforce on the center blade terminals may be interrupted by moving contact 36 away from contact 38.

To perform this operation, the center blade or actuator 44 is flexed downwardly until the force of the spring 45 flips the contact 36 upwardly. The button on the upper side of this contact then engages stationary contact 37. If a lead is connected with terminal 41 at this time, current will then flow through such lead. Termi nals 40 and 41 are' employed when a normally open switch action is required. When the center blade or actuator is released, it moves upwardly far enough to cause the spring to flip contact'36 downwardly again. When so moved the button on the underside of the contact reengages the lower stationary contact 38. Current flow from the line connected with contact 40 through the switch and the line connected with contact 42 will then be reestablished.

Motion is imparted to the center blade 44 from the exterior of the casing by depressing a push button 46 which projects from the top of the casing adjacent one end. This push button 46 forms a part of an assembly including a silicone rubber diaphragm 4-7, a ferrule 48 and a button guide and retainer 50. This assembly is soldered in place in a recess surrounding a hole formed in the top wall of the casing. By forming a recess, a flange against which the assembly may be abutted, is provided. in malting the assembly, the ferrule 48 is formed with an internal shoulder, the rubber diaphragm is set against the shoulder, then the button is placed with its head on the center of the diaphragm; following this step the retainer is slipped overthe reduced portion of the push bottom and the upper edge of the peripheral flange of the ferrule is turned down over the retainer. The diaphragm is molded with a washer-like edge having a downwardly extending portion guide retainer is shaped somewhat similarly but is spaced upwardly from the diaphragm to provide room for the push button.

The motion transmitting spring arm 32 is located with in-the casi ng; one endofthe arrriis disposed inregistration with the center of the diaphragm while the other end is secured to the under side of the casing top wall. In the form of the invention illustrated, the arm 32 is composed of a leaf spring section 51 and a dielectric diaphragm engagingsection '52. The resiliency of the diaphragm, the spring section 51 and the actuator 44 resists movement of the push-button and 'eflects its" return after it has been depressed. h

To hermetically seal the casing, the bottom wall is formed with a tubular eyelet 53 soldered into place and projecting downwardly from the bottom wall. Before the casing is assembled on the base 21, after the parts have been mounted in the casing, the air maybe exhausted from the interior and the tube 53 collapsed and if necessary soldered. It is within the'concept of the invention to fill the casing with a suitable gas if desired.

- After the casing has been evacuated, the base may be applied thereto, the posts 33, 34 and 35 being inserted into sockets formed on the inner ends of the terminal members 44 41 and 42. Y Y

Suitable openings 54 may be formed in the casing below the bottom wall 28 for mounting the switch.

While the form ofembodiment of the present invention as herein disclosed constitutes a preferred form, it isto be understood that other forms might be adopted, all coming within the scope of the claims WhiChfOllOW;

We claim:

1."In a hermetically sealed switch, a closed casing having an opening formed therein; a snap switch disposed in said casing, said switch having a movable operating memher; a ferrule secured in the opening in said casing; a flexible rubber diaphragm clamped in place in said ferrule; a push button supported in place in registration with the central portion of said diaphragm; and means for guiding-and retaining said push button, said means being secured in place by said ferrule.

2. A hermetically sealed switch comprising a casing having a metallic top wall with a depending peripheral wall forming a continuous internal shoulder; a metallic bottomwall engaging said shoulder and joined to said peripheral wall in gas tight relationship; a snap switch assembly having a movable operating member; means extending through openings in said bottom wall to support said snap switch assembly in said casing said means being connected with said bottom wall in electrically insulated gas tight relationship; a motion transmitting member connected at one end to the inside of said top wall, the latter wall having an opening registering with afree portion of said motion transmitting member; a flexible diaphragm secured over the opening in said top wall in gas tight relationship; and a push button supported adjacent said diaphragm, movement of said push button being transmitted by said diaphragm and motion transmitting member to the movable operating member of said switch assembly.

3. A hermetically sealed switch comprising a casing having a metallic top wall with depending peripheral wall formed with bottom Wall locating meansj'a metallic bot tom wall engaging said locating means arid=secured to said peripheral wall in gas tight relationship; a snap switch assembly having a movable operating member; means supporting said switch assembly in said casing, said means extending exteriorly of and being secured to said casing in electrically insulated gas tight relation shipga motion transmitting member connected at one end to the inside of said top wall, said top wall having a flanged opening registering with a free portion of said motion transmitting member; a ferrule engaging the flange in said opening and secured thereto in gas tight relationship; a flexible diaphragm supported by said ferrule to close the opening in said top wall; and a push button registering with said diaphragm, movement of said push button being transmitted by said diaphragm and said motion transmitting member to said switch operating member.

4. A hermetically sealed switch comprising a casing having a metallic top wall with a downwardly extending peripheral wall; a metallic bottom wall secured to said peripheral wall in gas tight relationship; a snap switch assembly having a movable operating member; combined conductor and switch supporting elements extending through said bottom wall; means securing said switch supporting elements to said bottom wall in electrically insulated gas tight relationship; a dielectric base; electrical connector elements carried by said base, said elements being formed to removably receive the exterior ends of said conductor and switch supporting elements upon assembly of said casing and base; a push button supported on the exterior of said top wall; and motion transmitting means between said push button and said switch operating member, a portion of said motion transmitting means being secured to said top wall in gas tight relationship.

5. A hermetically sealed switch comprising a casing having a metallic top wall with a downwardly extending peripheral wall;a metallic bottom wallsecured at its periphery to said peripheral wall in gas tight relationship; a snap switch assembly having a movable operating member', combination conductor and switch supporting elements extending from said switch assembly through said bottom wall; means securing said switch supporting elements to said bottom wall in electrically. insulated gas tight relationship; a dielectric base; locating means formed on'said casing and base for engagement upon assembly; electrical connector elements carriedby said base, said elements being formed to removably receive the exterior ends of said conductor and switch supporting elements when the locating means on said casing and base are in engagement; a push button supported on the exterior of said top wall; and motion transmitting meansbetween said push button and said switch operating member, a

portion of said motion transmitting means being secured to said top wall in gas tight relationship.

e 6. A hermetically sealed switch comprising: an enclosed casing sealed gas-tight excepting for an opening in a wall of the casing; a snap switch assembly having a movable operating member within said sealed casing; terminal means extending from said snap switch assembly to the outside of said casing, said means being in electrically insulated gas-tight relationship with said casing; a motion transmitting member connected at one end to a wall on the inside of said casing with a movable portion of said'member adjacent said opening in the casing; a flexible diaphragm secured over said wall opening in gas-tight relationship whereby the casing is sealed; movable switch actuator means supportedadjacent said diaphragm on the outside of said casing so that its motion can be transmitted by said diaphragm to said motion transmitting member and thence to said movable operating member for operation of the snap switch.

References Cited in the file of this patent Great Britain Apr. 6, 1939 

